Rotary actuator



June 22, 1965 Filed May 2, 1965 Fig.1

ROTARY ACTUATOR 2 Sheets-Sheet l 20. 2. -41- y m; I :64

INVENTORS EDWARD H. RUDD BY ELDON 0- SULLIVAN June 22, 1965 E. H. RMUDD ETAL 3,190,190

ROTARY ACTUATOR Filed May 2, 1963 2 Sheets-Sheet 2 Fig. 4

INVENTORS EDWARD H. RUDD BY ELDON 0. SULLIVAN 9464221? H'Mw, W

United States Patent 3,19%,H9 ROTARY ACTUATQR Edward H. Rudd, Wooster, and Eldon D. Sullivan, Orrviile, Ohio, assignors to Flo-Turk, Inc. Filed May 2, 1963, Ser. No. 277,551 14 Claims. {CL 926S) This invention relates generally to fluid actuators, and more specifically to a novel and improved fluid actuated, rotary actuator.

In general, the actuator is of the type having a reversible gear or pinion which isactuated inopposite directions by cooperating racks. Reciprocation of the racks is obtained by the action of fluid piston-cylinder mechanisms arranged in a suitable housing. While it is recognized that this general construction is embodied in many con ventional actuators, the present invention provides an improved arrangement of the piston-cylinder mechanisms in a unit which is characterized by its compactness. Because of its novel, compact construction, the actuator of this invention can be employed in applications in which the space requirements will not permit the use ofthe larger, conventional actuators wherein the fluid cylinders usually extend in opposite directions from the center line of the pinion. Typical of such applications are many ball valve installations wherein the space available to accommodate the valve actuating mechanism is limited.

Another important feature of the invention is a novel multiple cylinder operation which achieves reciprocal movement of the racks and consequent rotation of the pinion by the application of semi-balanced torque. To this end, the preferred embodiment of the invention contemplates a construction comprising a plurality of pistons operatively connected to each pinion rack. Two fluid sys tems are provided in connection with the several cylin ders in which the pistons are mounted and are adapted selectively to be pressurized and exhausted in such a manner that the driving force for rotating therpinion is applied to each rack. In the preferred, compact arrange-' ment of the invention, the driving force efiected by the fluid systems is applied to corresponding ends of the rack on one side of the pinion centerline. By rotating the pinion through the multiple cylinder operation which ob when taken in conjunction with the accompanying drawings.

In the drawings: a I

FIGURE 1 is a vertical cross-sectional view-of the preferred actuator construction comprising the present invention;

FIGURE 2 is a cross-sectional view taken onl the line 22 of FIG. 1;

FIGURE 3 is atop plan view taken on the;line 33 of FIG FIGURE 4 is a bottom plan view of the actuator; and FIGURE 5 is a view diagrammatically illustrating the fluid systems of the actuator.

Within the housing 11 is a pinion chamber 14 which opens through the flange 13 and through the opposite end of the body portion 12.

A pinion 20 is mounted in the pinion chamber 14. According to the preferred construction, ,the pinion is fixed on a shaft 21 which is rotatably mounted in the housing by bushings 22. As shown, the shaft 21 is tubular and extends through the opening of the pinion chamber in the flange 13. With this arrangement, the shaft 21 is adapted to be connected to a valve stem or other rotatable elernent (not shown) which may extend through the shaft and the housing 11. Preferably, O-rings 23 are provided between the shaft 21, the bushings 22 and the inner walls of the housing and-internally of the shaft between the shaft and the valve stem to seal the pinion chamber 14. i r

The mechanism for rotating the pinion 20 includes a pair of racks 28 and 29 which extend into the pinion chamber 14 in meshing engagement with the pinion. The rack 28 has an enlarged end which defines a piston 30. A piston rod 31 is connected to the enlarged end of the rack 28 and is provided with a second piston 32 which is axially spaced from the piston 30. The construction of the rack 29 is similar to that of the rack 28 and includes a piston 33, a piston rod 34 connected to the rack, and a second axially spaced piston 35. In the illustrated embodiment of this invention, the piston rods 31 and 34 are respectively connected to the racks 28 and 29 so as to extend in the same direction on one side of the pinion 20. While two pistons have been shown and described as being connected to each rack, it will be apparent that the number of pistons. can be increased in order to produce the desired driving force on the output shaft 21. 1

The housing 11 is shown as having parallel cylinder bores 40 and 41. Cylinder casings 42 and 43 are mounted in the lower portions of the bores 40 and 41, respectively, and these casings are provided with end closing plates 44 and, 45. The upper portions of the bores 40 and 41,

a as viewed in FIG. 1, are in communication with the pinion chamber 14 and define cylinders for the pistons 30 and 33, respectively. The-pistons 32 and 35 are respectivelymounted in the cylinder casings 42 and 43 with the piston rods 31 and 34 extending through the upper provided in connection with the several cylinders so that the pinion 20 can be rotated by the application of semipressure chamber '51 is in constant fluid communication with another pressure chamber 52 behind the piston 32.

'The two pressure chambers are maintained in fluid communciation by a passage54 through the piston rod 31.

The pressure chamber'Sl also is in communication with a third "pressure chamber 53 above the piston 35. In the form of the'invention shown, this communication is es- Referring now to the drawings, the preferred embodimerit of the actuator is generally designated by reference numeral 10. As shown, the actuator 10 includes a housing 11 having a body portion 12 and an integral mounting flange or face plate 13 at one end of the body portion.

tablished' by a passage 55 formed in the housing body 12 thewall of the casing 43. I

The second fluidsystem is similar to the system just described andincludes a' fluid passage .60 (FIG. 3) in the 63 abovethe piston 32.

q 3 housing body 12 which communicates with a first pres sure chamber 61 behind the piston 33., The chamber 61 is connected to a second pressure chamber 62'behind the piston.35 by. a passage .64 in the piston rod 34, and to a third pressure chamber 63 above the piston ,32. The 7 pressure chambers 61 and 63 are connected by a passage 65 (FIG, 4) which isbetWeen the bores40 and -'41 and parallel to the passage 55. This passage 65 is ported through the walls of the bore 41 above thecasingj43 and into a groove 66 which communicateswith the chamber Both of the passages 50 and'tl are adapted alternately to beconnected to asource of'fluid under pressure and to exhaust, whereby one fluid system can "be pressurized While the other is exhausted. These fluid connections may be formed by conduits (not shown) connected to the housing 11 in communication with'the openingsof 'the passages. A conventional reversing valve (also not shown) is preferably provided in the conduits fso that each conduit can be selectively pressurized and exhausted and so that both conduits can be shut olf from the fluid source and from exhaust. V

The pinion chamber 14 and the communicating cylinder bores 40and 41abovethe pistons 30fand 33' are preferablyfilled with 1 liquid. This liquid isconstantly agitated during rotation of the pinion and, while maintaining constant volume, is forced intoand out ,ofthecylinder bores by reciprocation of the racks. The liquid in the pinion chamber serves as alubricant for thepinion,

racks and O-rings. v 7

The operation ofthe actuator 10 will'be'most readily apparent by referring to FIG. 5. "When the passage 50 is connected to source, fluid .under pressure willbe admitted to the pressure chambers 51,51 and 53. The

pressure thus created in the chambers. El and 52 .acts on the pistons and 32'to force therack 28 up, as viewed in FIG. 5, while the pressure in the chamber53iacts on the piston to pull the rack 29 down, therebyrotating the pinion. 20 (not shown) counterclockwise bya "double cylinder operation. and semi-balanced torque. Atthe.

same time, the passage '60 is connected to exhaust so that fluid will be forced from chambers 61, 62 and '63. Reverse rotation of the pinion is obtained bycorinecting the.

'pas sagei60 .to source and the passage .50 to exhaust.

In this manner, the chambers 61, 62 and j63 are pressurizedwhile the fluid inthe'chambers 51, 52rjand'53 is exhausted.

AS be apparent from the above description,,the

P H QKi isrotatable in either .direction by adrivin'g force applied through each of the racks. This applicationlof semi-balanced torque is. an important ,feature of the.

invention,: since the pinion can .be accurately rotated vto position by disconnecting the fluidsystems-frorn source and from exhaust so thatvthey arein lockingbalance.

Since the fluid systems are in locking balance, the pinion will not creep beyond its adjusted position, as has been the case with many conventional actuators and any tendency of the pinion to .rotate because 'of-forces ape will be resisted. s V a V At the same time, the-foregoing multiple cylinder ,action' ,isobtained in a-construction whereinthe piston 'r'ods may extend in the same'direction instead of .in opposite directions.

Because of this novelv arrangement, the ac-.

anyjdesir'ed positionwithout binding or deflection cftthe pinion shaft. Further, the opinion can'beheldiin any fplied through the member connected re the pinion shaft tuator, of .this invention is of .a smaller, compac tconstruction than the'fluid-actuatei'rotary actuators of the prior art. f

7 Many modifications and variations ofthe invention will be apparent to thoseskill'ed inthefart in view ofthe foregoingdetailed disclosure. Therefore,,it is to be un-' derstood that, withinthe scope 'oftheappended' claims,

the invention can be practiced otherwiseithan :as' specificallyshown and described.

4 i What is claimed is: a 1. A fluid actuator comprising: (a) a housing, (b) a shaft journaled in said housing, 7 (c) first and second drive means in said housing on one side of said shaft,said drive meansbeing operatively connected to said shaft, Y

(d) and first and secondfluid systems'c ac h being operatively connected to each of saiddrive means, 1 v (e) said first fluid system including means for applying fluid pressure to both of said drive means to rotate said. shaft in one direction, and said second fluid system including means for applying fluidjpr'essure to both of said drive means to. rotatefsaid'shaft inthe opposite direction; 7 a 12. A fluid actuator comprising:

(a) a housing, a I (b') a shaft journaled in said housing, V (c) first and second rack means drivingly connected to said shaft in diametrical' Opposition, in V (d) 'first fluid power means including means for applying fluid pressure simultaneously to both-iof said. rack means to rotate said'shaft in onedirection, and.

.(e) second fluid power means including :rn'eansf for said racks, said piston "rods extendingrin the' same direction on one side of said pinion, (e) apiston connected to each rod, and p (f) a fluid system including means for simultaneously applying fluidpressure ahead of one of saidpi'stons and behind the "other of said pistons and "for'selecr. tively reversing the application of fluid pressure to each piston so'that said racks can begmoved inop posite directions to rotate said pinion. 4. A fluid actuator comprising: H

' (a) a housing having-a pinion chamber,

(b) a pinion journaledin :said chamber, (c) a pair of racks in driving engaement withsa'id pinion, i

l(d) aplurality f'axially spaced pistons co nne cted'to each'of'said racks,

(e) a manual system including means 7 for selectively applying and exhausting flnid pressure oncorrew sponding surfaces of thepistons on oneof said racks and on an opposite surface. of a pistonon the" other of said racks, and f j v (f) a second fluid system including meansv for 86139-2 tive'ly applying and exhausting fluid pressure on corresponding surfaces of .the pistons 'on' said other rack and on aniopposite surface of a piston on said one rack,

(g) said fluid; systems being alternately operable to-- 6btain movement 'o'f said racks in oppositedirectionsv plication' ofsemi-balanc'edtorque; I H

5. The actuatorias iclaimed in 'claim 4 wherein said means of 'said'first'fluid system comprises anpres'sure chamberbehind the pistons of v one of said racksjand ahead of one piston of the other ofsa'idracksg and where-1 j in the mean sloffsaidsecond 'fluid system comprises a pressure chamber. behind the pistons of said ctheri'r'ac'k and ahead ofa piston of said, one rack;

6. A fluid actuator comprising:

" "(a,) a'hous'ing havinga'pi riionchamber,

. and consequent rotation of saidpinionby the ap-:'

ing surfaces of the pistons on one of said rods and r on an opposite surface of a piston on the other of said rods, and

(g) a second fluid system including means for selectively applying and exhausting fluid pressure on corresponding surfaces of the pistons on said other rod and on an opposite surface of a piston on said one rod,

(h) said fluid systems being alternately operable to obtain movement of said racks in opposite directions and consequent rotation of the pinion by the application of semi-balanced torque.

7. A fluid actuator comprising:

(a) a housing having a pinion chamber,

(b) a pinion journaled in said chamber,"

(c) a pair of racks in driving engagement with said pinion,

(d) a pair of piston rods individually connected to said racks, said piston rods extending in the same direction on one side of said pinion,

(e) two axially spaced pistons connected to each of said rods,

(f) a first fluid system comprising a pressure chamber behind the pistons of one of said rods and ahead of one of said pistons of the other of said rods, and

(g) a second fluid system comprising a pressure chamber behind the pistons of said other rod andahead of a piston of said one rod,

(h) said fluid system being adapted to be alternately connected to a pressure source and to exhaust so that said racks can be moved in opposite directions to rotate said pinion by the applications of semi-balanced torque.

8. A fluid actuator comprising:

(a) a housing having a pinion chamber and spaced,

parallel cylinders,

(b) a pinion journaled in said pinion chamber,

(c) a pair of racks in driving engagement with said pinion,

(d) a pair of piston rods individually connected to said racks, said piston rods extending in the same direction on one side of said pinion,

' (e) a piston connected to each of said rods in one of said cylinders,

(f) a first fluid pressure system connecting said cylinders for selectively applying an exhausting fluid pressure behind one of said pistons and ahead of the other of said pistons, and V (g) a second fluid pressure system connecting said cylinders for selectively applying an exhausting fluid pressure ahead of said onepiston and behind .said other piston, a

(h) said fluid systems being alternately operable to obtain movement of said racks in opposite directions in consequent rotation of said pinion by the application of semi-balanced torque.

9.A fluid actuator as claimed in claim 6 including a second piston connected to each of said rods, said housing having a cylinder for each of said second pistons, said first fluid system being connected to the cylinder area behind the second piston of said one rod, and said second fluid system being connected to the cylinder area behind the second piston of said other rod.

it). A fluid actuator as claimed in claim 9 wherein the cylinder areas ahead of said second pistons are in communication with said pinion chamber.

11. A fluid actuator comprising: (a) a housing having a pinion-chamber, (b) a pinion journaled in said chamber, (c) a pair of racks in driving engagement with said pinion, 1

(d) a pair of pistons connected to each rack, said pistons being disposed on the same side of a diameter of said pinion,

(e) a first fluid system operatively connected to the pistons of one rack for applying pressure in one direction and to a piston of the other rack for applying pressure in the opposite direction, and

(f) a second fluid system operatively connected to the pistons of said other rack for applying pressure in said one direction and to a piston of said one rack for applying pressure in said opposite direction,

(g) said fluid systems being adapted to be selectively connected to a pressure source and to exhaust so that said racks can be reciprocated in opposite directions to rotate said pinion.

12. The actuator as claimed in claim 11 wherein the.

total surface area of said pistons in each of said fluid systems is equal. t

13. The actuator as claimed in claim 12 wherein said fluid systems include cylinders in said housing for each of said pistons, and wherein the cylinders for a corresponding piston connected to each rack are in communication With said pinion chamber.

14. A fluid actuator comprising:

(a) a housing,

(b) a shaft journaled in said housing,

(0) rack means drivingly connected to said shaft for rotating said shaft in opposite directions, (d) first and second groups of pistons connected to said rack means, both of said groups ofvpistons be-.

ing operable simultaneously to reciprocate said rack means, t

(e) a first fluid system operatively connected to the pistons of one of said groups and to a piston or" the other of said groups for applying fluid pressure thereto and causing rotation of said shaft in one direction, and

(f) a second fluid system operatively connected to the pistons of said other group and to a piston of said one group for applying fluid pressure thereto and causing rotation of said shaft in the tion, 7 c

(g) said fluid systems being alternately operable to obtain reciprocal movement of said rack means.

References Cited by the Examiner UNITED STATES PATENTS 1,271,569 7/18 Hancock 92l36 2,168,215 8/39 Keitel 92136 3,019,771 2/62 Heese et al. 92136 3,040,717 6/62 Rumsey 9268 RICHARD B. WILKINSON, Primary Examiner.

opposite direc-. 

1. A FLUID ACTUATOR COMPRISING: (A) A HOUSING, (B) A SHAFT JOURNALED IN SAID HOUSING, (C) FIRST AND SECOND DRIVE MEANS IN SAID HOUSING ON ONE SIDE OF SAID SHAFT, SAID DRIVE MEANS BEING OPERATIVELY CONNECTED TO SAID SHAFT, (D) AND FIRST AND SECOND FLUID SYSTEMS EACH BEING OPERATIVELY CONNECTED TO EACH OF SAID DRIVE MEANS, (E) SAID FIRST FLUID SYSTEM INCLUDING MEANS FOR APPLYING FLUID PRESSURE TO BOTH OF SAID DRIVE MEANS TO ROTATE SAID SHAFT IN ONE DIRECTION, AND SAID SECOND FLUID SYSTEM INCLUDING MEANS FOR APPLYING FLUID PRESSURE TO BOTH OF SAID DIRVE MEANS TO ROTATE SAID SHAFT IN THE OPPOSITE DIRECTION. 